Production of secondary and tertiary halogenated alcohols



Patented Aug. 3, 1948 UNITED STATES PATENT OFFICE PRODUCTION OFSECONDARY AND TER- TIARY HALOGENATED ALCOHOLS Ernst Bergmann and MaxSulzbacher, London, England, assignors to Polymerisable ProductsLimited, London, England, a British company No Drawing. ApplicationFebruary 3, 1945, Serial No. 576,150. In Great Britain March 13, 1944 11Claims. (01. 26 618) larly in the sense of the scheme:

R C] R 01 t t t |=0 C1|H HO- -01 H 01 OH 51 aldehyde polyhalogencompoundSpecifically, as polyhalogenated compounds, chloroform or bromoform canbe employed. In U. S. A. application No. 510,700 of Ernst Bergmann,filed Nov. 17, 1943, the production of acetone-chloroform has beendescribed, using as a most successful condensing agent the novel complexbetween potassium hydroxide and organic solvents containing two etheroxygen atoms, separated by at least one and not more than two carbonatoms, particularly acetals and ethyleneglycol, dialkyl-ethers. Suchcomplexes have been described in the U. S. A. applications No. 464,790,now abandoned, No. 493,301, now abandoned, and 583,177 of our co-workerDr. Chas. Weizmann (this latter now Patent No. 2,435,524), and No.510,700 and N 0. 514,727 of Ernst Bergmann.

We have now found that these complexes bring about the condensation onthe one hand of trihalogeno-methanes and on the other hand, aldehydes.In most cases the yields are very satisfactory and reaction takes placein cases in which other condensing agents are without effect. Care mustalso be taken that the speed of self-condensation of the aldehydes issubstantially lower,

under the conditions employed than that of the reaction with chloroformor bromoform.

Aldehydes especially suitable are for that reason benzaldehydes (as anexample of aromatic aldehydes) and branched aliphatic aldehydes, such asisobutyraldehyde and 2-ethyl-hexanal (as examples of aliphaticaldehydes).

The reaction has preferably to be carried out at low temperature and itis advisable to discontinue the treatment when-the conversion hasreached about 85%. This prevents undue dehalogenation of the organichalogen compounds, and the unreacted aldehyde and chloroform can berecovered and re-used in subsequent runs of the process.

The potassium hydroxide employed is nearly all recovered in the form ofan aqueous solution of about concentration, by treating the reactionproduct with an appropriate amount of ice or ice water, thus hydrolysingthe potassium salt of 2 the halogenated alcohol. From the said aqueoussolution the solid potassium hydroxide can be recovered in anappropriate way, e. g. by distilling off the water in the presence ofappropriate organic solvents such as the above acetals andglycol-ethers.

Obviously, the reaction product can also be worked up by treatment witha dilute aqueous acid; in this case, however, the potassium hydroxidecannot easily be, recovered. a

The following examples show how the reaction can .be carried intoeffect, but the invention is not limited to these examples:

Example 1.-1.1.1 trz'chloro-3-ethyl-heptanol- (2) The complex wasprepared from 250 cc. dry methylal and g. potassium hydroxide'powder,containing 51 g. (0.9 mol.) pure KOH, at -2 C. and a mixture of 107.5 g.(0.9 mol.) chloroform and 128 g. 2-ethyl-hexanal (1 mol.) was added at-3 C. The mixture was agitated at the same temperature for further twohours and decomposed with ice water. The following fractions weresecured:

Methylal 40-45 C. chloroform, 37.0 g.=34.4%

of the initial amount 58-65 C.- Z-ethyl-hexanal, 55.0 g.

=43.0% of the initial amount -88 0/16 mm.

1.1.1-trichloro- 3 -ethyl-heptanol-(2), 120.0 g.=53.9% of the theory l40This chlorinated alcohol,

CI'kCHaCI-IaCHaCH(C2H5).CHOH.CC13

is a new compound; it forms a slightly yellowish oil. This is insolublein water, soluble in most organic solvents (including light petroleumdistillates). At about --40 C. it solidifies to a glassy mass.

Found: (143.9; H, 7.0; 01, 42.5. Calc. for C9H17OC13: C, 43.6; H, 6.9;Cl, 43.0.

Example 2.--Trichloromethyl-isopropyl-carbinol 60 g. potassium hydroxidepowder, correspond- C./l6 mm.

'ing to 51 g. (0.9 mol.) pure KOH, were converted into the complex with250 cc. of dry methylal at 2 C. A mixture of 107.5 g. (0.9 mol.)chloroform and 72 g. (1 mol.) isobutyraldehyde (B. F.

'61) was slowly added to the fine, well-agitated suspension during onehour, the internal temperature being kept at about -4 C. The agitationwas continued for a further two hours at -2. The mixture was decomposedwith ice water and dilute sulphuric acid and the methylal solutionseparated and thoroughly dried with anhydrous 3 Fractional distillation.gave: At 40-45 C. Methylal At 5870 C. mixture of unreacted chloroformand isobutyraldehyde At 125-135 C. redistilled B. P. 125-130,tri'chloromethyl-isopropyl-carbinol, a pale yellow liquid, 24.8 g.=1414.4% of the theoretical amount. It will be understood that in placeof the acetals mentioned, other solvents of the above-defined type canbe similarly employed. Thev amount of such solvent can vary between widelimits. Such bodies contain in their molecule two ether-forming oxygenatoms separated from each other .by not more than two carbon atoms, 1.e.

where R may represent the same or different hydrocarbon radicles and R"may represent hydrogen or the same or different hydrocarbon radicles.

As examples of suitable solvents, which form stable complexes withpotassium hydroxide, the following may be mentioned:

The acetal fromw Z-ethyl-hexanal and; methyl alcohol.

The acetal from methyl-ethyl-ketone and ethylene glycol.

The acetal from formaldehyde and propylene glycol.

Acetaldehyde dibutyl acetal.

The acetal from acetone and butyl alcohol.

Ethylene-glycol-ethyl-butyl ether.

EthyIene-glyccl-dibutyl-ether.

Propylene-glycol-ethyl-butyl-ether.

The use of certain aldehydes may present difiiculties, as the speed ofself-condensation is in some cases commensurate with that ofthe reactionwith chloroform. In the instances where this is not the case, thereaction is very smooth, as for example in the case of benzaldehyde andbranched aliphatic aldehydes such as isobutyraldehyde and2-ethyl-hexanal..

What we claim and desire tosecu-rew by Letters Patent is:

1'. In making a tri-halogenated. alcohol, the process which comprisesreacting together at about ice temperature, about GL9 mol. of atrihalogen methane with about 1 mol.,of an aldehyde containing at leastfour carbon atoms to the molecule, in the presenceoi about 0.9 mol. ofcaustic potash in the form of a solid complex with a, substance selectedfrom the group consisting of acetals and dialkyl ethers of glycols and asubstantial excess of such latter substance whichtsubstance-contains inits molecule two and only twoether-forming; oxygen atoms which areseparated from each other by at least one and not more than two carbonatoms, and stopping the reaction, when sufiiciently completed by addingan excess of a substantially ice-cold. aqueous substance which is inertto the metal-free organic substances present. 1

2; A. process asin claim 1 in which the reaction is allowed tocontinueonly until about. 85% com.- pleted.

3 A. process asinv claim 1. in which the. product of the first reactionis mixed. with enough H2O at about ice temperature to react with all. ofthe organically combined potassium present in the reaction product withthe production of an aqueous KOH solution of about 3.0 concentration.

4. A process of producing a halogenated alcohol which comprises reactingunder refrigeration, a tri-halogeno-methane with an aldehyde containingat least four carbon atoms to the molecule, in the presence of causticpotash in the form of a solid complex with a substance selected from thegroup consisting of acetals and dialkyl ethers of glycols and asubstantial excess of such latter substance, which said substancecontains in its molecule two and only two ether-forming oxygen atomswhich are separated from each other by at least one and not more thantwo carbon atoms.

5. A process as in claim 4, in which the substance selected from thegroup consisting of acetals and dialkyl ethers of glycols, is free fromany hydroxyl groups.

6. A process as in claim 4, in which the said aldehyde contains abranched hydrocarbon chain in which the branching is at the carbon.-atom immediately adjacent the aldehyde group.

7. A process as in claim 4, in which the trihalogeno-methane ischloroform.

8. A process which comprises condensing, atrihalogeno-methane withz-ethyl-hexanal', in the presence of caustic potash in the form of asolid complex with a substance selected from the group consisting ofacetals and dialkyl ethers; of glycols and a substantial excess of suchlatter substance, which said substance contains in its molecule two andonly two ether-forming oxygen atoms which are separated from each otherby at least one and not more than two carbon atoms.

- 9. A process according to. claim 4 in which the condensation is thatbetween chloroform and 2.- ethyl-hexanal. V

10. The new chemical compound 1.1..L-trichloro-3-ethyl-heptanol(2) 11.A. process of producing a. halogenated alcohol whichcomprises reacting,under refrigeration and at about ice temperature, a trihalogenomethanewithan aldehydeselectedirom the group consisting of branched chainaliphatic aldehydes and. aromatic aldehydes, in the. presence. of asolidcomplex of potassium hydroxide and a. substance selected from. the groupconsisting of acetals and dialkyl ethers of glycols, and a substantialexcess of said latter substance, which said substance contains in itsmolecule two. andv only two etheriorming oxygen atoms which areseparated. from each. other by at least. one and not more than twocarbon atoms,v and thereafter hydrolyzing. the potassium derivative ofthe halogenated alcohol so. produced.

ERNST BERGMANBL MAX SULZBACHER.

REFERENCES GITED The following. references. are of record. in. the

file. of. this patent:

UNITED STATES Pi UiiElqltil.

Number Name Date 761,189 Aldrich May 30, 1904 777,712 Aldrich Dec; 20,1904 2,161,191 Perkins June 6, 1939 2,345,170 Z'eltner Mar. 28, 1 944FOREIGN PATENTS Number Country Date 515,539 Germany Jan; 13, 1931 OTHERREFERENCES Howard et, al.: Jour... Am. Chem- Soc... vol. 60, 228-9(1938).

Hansen et al.: Chem. Soc. J our. (1944). 74-5.

